There is a great demand for reduced fat prepared food products, especially vegetable and animal-derived fried food products, such as potato chips, fried fast food products, and cheeses. Consequently, the food industry is spending substantial sums of money to bring such products to market. One challenge, particularly for fast food producers is to make a product which is substantially reduced in fat content, but which is still appealing to consumers' taste buds. All too often, these two competing interests are mutually exclusive. There are no commercial processes available wherein vegetable and animal-based food products are first fried, then treated to remove oil, particularly the cooking oil used for frying and still have a good tasting food product. It is conventional wisdom in the food industry that in order to produce a reduced fat food product a process other than frying in cooking oil must be used.
There have been numerous processes proposed to produce snack food products having the palate appeal of fried food products, but being substantially fat-free. Unfortunately, none of these processes has met with a great deal of success. The typical commercial process attempts to produce a food product, such as potato chips without frying, but which they hope will have the flavor of fried products.
For example, U.S. Pat. No. 4,756,916 teaches a process for producing low-fat potato chips comprising washing potato slices with an aqueous solution, then applying oil to the washed slices to coat the slices with oil. The amount of oil applied to the washed slices is adjusted to achieve an oil content of about 10 to 25 wt. % in the final product. The oil coated slices are blanched, essentially pre-frying the slices due to the oil coating, then baked at a temperature of at least about 390.degree. F. to partially dry the slices. The partially dried potato slices are then baked at a temperature of about 290.degree. F. (140.degree. C.) to 320.degree. F. (160.degree. C.) to finish drying the slices.
Another technique is taught in U.S. Pat. No. 4,906,483 which is directed to a process for producing potato products having no-fat, no-cholesterol, and no salt ingredient characteristics. This is done by placing a pan, containing previously rinsed and sliced potatoes submerged in water, into a microwave oven until the submerged potatoes are visibly transparent. The hot water is then replaced with cold water to remove visible starch. The potatoes are rinsed and arranged on a non-stick cooking sheet and placed in a conventional oven for browning and crisping. Such a process fails to achieve the taste benefits that would be derived from frying the potatoes in cooking oil. Furthermore, extra steps are needed wherein a microwave and a conventional oven are used. Similarly, U.S. Pat. No. 5,202,139 discloses a process for preparing essentially fat-free potato chips. The process involves slicing and washing raw potatoes, pre-drying and arranging the sliced potatoes on a conveyor, then exposing them to a high intensity microwave field. The potato slices are then seasoned and exposed to a lower intensity microwave field. Such a process is not only limited by the fact that it does not achieve the taste advantage from frying, but the process itself is limited to producing only a single layer of product at a time. This limitation is due to the nature of microwave cooking and thus will result in less efficient chip production than a process that can cook or fry multiple layers of sliced food product.
Further, U.S. Pat. No. 4,919,965 discloses a method of toasting agricultural produce slices and, more particularly, potato slices. The toasting process takes place by the use of compressive, opposed, contact surfaces, which toast the sliced produce in a fat and oil-free environment. More specifically, the process of this reference includes washing raw agricultural produce, then slicing the produce into thin slices. A seasoning is then applied to the slices which are then cooked under heat and pressure imposed between an opposing pair of heating surfaces to drive out moisture and toast the slices.
Also, U.S. Pat. No. 4,873,093 discloses a product and process for preparing a baked snack food from gelatinized starch ingredients wherein at least one ingredient having starch, such as potatoes, is mixed with water to form a composition which is steamed to form a dough-like consistency. The dough-like composition is then machined to form pieces, which are baked in a conventional oven. The exterior layer of the dough-like composition cooks rapidly during baking and traps steam in the interior portion of the dough. An alternative embodiment includes spraying vegetable oil onto the pieces prior to baking to obtain a final product having a flat, oil-containing cracker-like appearance. A post-bake oil application is optional and included in a preferred embodiment.
U.S. Pat. No. 5,298,707 teaches a process and apparatus for preparing fat-free snack chips by exposing sliced raw potatoes, and the like, to a high intensity microwave field that rapidly converts moisture within the slice to steam. The exposed slices are then dried by longer exposure to a lower energy microwave field with an elaborate microwave apparatus. The resulting chip product, which has not been fried in oil, will lack the flavor, which appeals to the typical consumer of snack foods.
Another attempt at making fat-free snack foods is taught in U.S. Pat. No. 5,370,838 which discloses a process for producing food chip products which does not involve oil-based cooking. The process includes slicing and/or shaping a food, such as potatoes, then washing starch from the sliced, or shaped food, with water then forming multiple layers of the food product. The multiple-layered food product is baked in an impingement oven under conditions sufficient to form a fluidized bed of layered food product. The pressure is varied within the impingement oven to further release moisture. After baking, the shaped food forms are dried and optionally seasoned. This process, like those previously discussed, fails to produce a fried snack product substantially free of oil and which still has most, of not all, of the flavor generated by the frying step.
Therefore, there is a substantial need and commercial demand in the art for a process which is able to produce a prepared food product, such as a fried food product, that is substantially free of oils and fats and which still has significant taste appeal to the typical snack food consumer.